Do Thi-Nga, Shih Po-Hsin, Gumbs Godfrey
Department of Physics, National Cheng Kung University, Tainan 701, Taiwan.
Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, NY 10065, United States of America.
J Phys Condens Matter. 2023 Aug 10;35(45). doi: 10.1088/1361-648X/acecf1.
The magic-angle twisted bilayer graphene (MATBLG) has been demonstrated to exhibit exotic physical properties due to the special flat bands. However, exploiting the engineering of such properties by external fields is still in it infancy. Here we show that MATBLG under an external magnetic field presents a distinctive magnetoplasmon dispersion, which can be significantly modified by transferred momentum and charge doping. Along a wide range of transferred momentum, there exist special pronounced single magnetoplasmon and horizontal single-particle excitation modes near charge neutrality. We provide an insightful discussion of such unique features based on the electronic excitation of Landau levels quantized from the flat bands and Landau damping. Additionally, charge doping leads to peculiar multiple strong-weight magnetoplasmons. These characteristics make MATBLG a favorable candidate for plasmonic devices and technology applications.
魔角扭曲双层石墨烯（MATBLG）已被证明由于其特殊的平带而展现出奇异的物理性质。然而，利用外部场对这些性质进行调控仍处于起步阶段。在此我们表明，处于外部磁场中的MATBLG呈现出独特的磁等离子体色散，其可通过转移动量和电荷掺杂得到显著改变。在较宽的转移动量范围内，在电荷中性附近存在特殊的明显单磁等离子体和水平单粒子激发模式。我们基于从平带量子化的朗道能级的电子激发和朗道阻尼，对这些独特特征进行了深入讨论。此外，电荷掺杂导致了奇特的多个强权重磁等离子体。这些特性使MATBLG成为等离子体器件和技术应用的理想候选材料。
